Other than India (Hinduism), it could be Islam or possibly Buddhism.
Hindu, Islam, and i think Jainism
Christianity became dominant as a result of the European colonization of the Caribbean. Hinduism and Islam became prevalent because of the importation of labor from the Indian Subcontinent which is dominated by Hinduism and Islam.
It depends on the timing. The first Muslim conquest of territories on the Indian periphery was the conquest of Sindh by Muhammed bin Qasim of the Umayyad Caliphate from 711-715. He, and the army he led, were primarily composed of Arabs, not Turks. The Umayyad Caliphate brough Islam to the areas it had conquered, but was ineffective at spreading Islam throughout the subcontinent. However, in the subsequent centuries, the Turkic Seljuqs, Timurids, and Mughals would all conquer areas on the Indian perimeter with the Mughals penetrating deep into the subcontinent. As a result, the Mughals were far more effective at spreading Islam deep into India.
The Minangukabau
Islam
North Africa is heavily dominated by Islam.
By trading vessels sailing out of Muslim lands across to the hind.
Islam
There have been many Muslim Empires dominated by Islam. The last Muslim Empire or Caliphate was Usmani Caliphate (also known as the Ottoman Empire) in Turkey.
The countries where there are more Shia than Sunni and where sunni muslims are persecuted for their beliefs are mainly Iran and Iraq, where the shiia population is over 90%
Islam is his religion by surname. He is a Khan of Bollywood. Khans are said to have dominated the Industry